Key to a Promise
by Rivulet027
Summary: Harry Potter/BTVS x-over. Basic season seven. Dawn's keyness accidently sends her to Hogworts and Willow keeps a promise to Tara. WillowSnape
1. The Spell

Disclaimer: I own nothing to do with Buffy, it's not my toy box. I own nothing to do with the world of Harry Potter, it to is not my toy box. I am merely burrowing charactors from both those toy boxes and getting them intermingled.I also own nothing to do with Allan Zola Kronzek and Elizabeth Kronzek's Harry Potter book.

Note: This piece is dedicated to my cousin who kinda looks like Dawn and we've always affectionately called Little Bit. This story has been playing with me for awhile. It's a direct result from loving the Buffy episode Fear Itself. I love how just a little of Oz's blood caused the spell to work. So the idea began to play with me about Dawn. This is also a result of watching this season and not seeing Dawn for awhile and missing her. This is also a result of my craving a little Willow/Snape in my writing. I hope you enjoy it, if not I'm sorry I wasted your time. Oh and as a warning this is mostly BTVS with just a dash of Harry Potter. Spoliers are everything up to GoF for Harry Potter and for Buffy it's basic season seven.

So with everything said onto the story:

"Have you got everything?" the girl asked as the two snuck into the science room after school.

"Don't worry about it. You got the book?" the boy asked.

In reply the girl pulled out a well worn, obviously well read copy, of Harry Potter and the Goblet of Fire. The boy eyed it suspiciously before telling her, "That's not your copy. I know you didn't read it that many times."

"Of course it's not," the girl retorted, "You think I'm going to mark up my copy. I borrowed it from that Summer's girl."

"Does she know you have it?"

"No. I'm not stupid. I took it from her bag during English."

"Did she see?"

"She was in the bathroom."

The boy nodded before turning the book over in his hands. He flipped it opened and looked it at it a bit, "What's all this writing in the front?"

The girl shrugged, "Weird notes and stuff. Girl's funny, what do you expect? Why will it affect our spell?"

The boy wrinkled his nose as he thought over her question, "I don't think it will. It shouldn't. We're going to put the spell in the back anyway."

Unceremoniously they dropped their backpack on the floor and sat. The boy began pulling ingredients for the spell out of his. He opened an old leather bound book to a marked page and began copying symbols from it on the inside of the back cover of the Harry Potter book.

The girl remained silent, watching a moment before asking, "Are you sure this will work?"

"Well," the boy told her, "if it does work we'll be transported to their seventh year."

"Seventh year? Why seventh? If we're actually going why not when their our age? I want to seduce..."

The boy cut her off, "Sue, this isn't about your stupid crush."

"What's it about then?"

"Learning magic, real magic, their kind of magic."

"I still want..."

"Sue, this is what we agreed to, are you in or out? I'll do the spell alone if I have to."

"I'm in. I'm in.

"Good, give me your hand."

Sue eyed him suspiciously a moment before asking, "Why?"

"The spell needs blood. Then it's done and we're gone."

"We are so not using my blood for anything."

"Sue come on. It has to be girls blood."

"I thought you didn't need me! I thought you could do it yourself!"

"I lied. Now stop being a stupid baby and give me your hand."

"Are you sure it will work?"

The boy sighed looking at her in a frustrated way, "No, I think the blood has to be mystical too, but then you've been practicing magic for a year so maybe."

She glared at him, "You are so not getting my blood!"

"Come on Sue!"

"I had reasons for doing this, and my crush is so not stupid. And what do you mean by mystical blood anyway, here let me see that book," she ended as she stuck out her hand to see the book he was copying from. He rolled his eyes and handed it to her. Her pale eyes quickly skimmed the page as a frown set itself upon her face.

After a moment she looked up at him and shook her head, "This isn't going to work. Mystical as in like a werewolf or vampire or something else that doesn't exist is what it means. This isn't possible and I am no longer in," she told him indignantly as she tossed him his book, gathered her things and stalked from the room.

Sighing he dropped the Harry Potter book on the ground and hurriedly gathered his things into his bag as he took of after her, "Sue wait!"

The book settled on the floor upside down.

Moments later two voices could be heard outside the room.

"This is the last one, then you leave," the janitor told Dawn Summers.

"But I have to find my book," Dawn protested anxiously.

As he opened the door she hurried past him searching the room. Her eyes settled on her beloved copy of Harry Potter. She picked it up with a cry of, "I found it! Oh thank you! You have no idea what this means to me! This book is so so special."

The janitor just shook his head. 


	2. Memories

Dawn clutched her book to her chest as she climbed into Xander's car. She couldn't believe she'd almost lost it. Stranger still was the classroom she found it in, she'd never even taken a class in that room. How it got in there was beyond her.

She smiled sheepishly at Xander, "Sorry, thanks for waiting."

"Forget your mind-numbing homework?"

"I couldn't find my book," Dawn informed him before she said, "Sorry you had to take time out to come pick me up."

Xander shrugged, "Buff got off early and has the whole day planned for the potentials, who was I to stand in the way of saving the world. So which book? It wasn't math was it? Cause if it was I'd say leave it, get Wills to do your homework. That's how your sister and I got... okay I didn't say that. Erase that statement from your memory."

She laughed and he actually gave her one of his goofy smiles. She missed those and they seemed to come less and less frequently now a days.

"No," she laughed enjoying the moment, "it was the most important one."

"And which one would that..." his voice tailed off as they pulled to a stop at the corner and he caught site of which book she held.

"Oh," he said with understanding, a slight pained look on his face.

Harry Potter and the Goblet of Fire, Dawn's most important book. At this point it was more important to her then even her journals. The Harry Potter book was a testament to how things use to be.

It started when Dawn began crushing on Ron. When she first read the books she'd been deep in her crushing on Xander stage and Ron had well reminded her of Xander. She had very carefully wrote Dawn loves Ron in the front cover of each of her four books.

Her mom had caught her and Dawn had declared that to make the situation less embarrassing her mom would just have to crush on someone. Her mom had thought the idea too cute and had complied by writing Joyce loves Remus in the front cover of Dawn's copy of Goblet of Fire. Dawn's gales of laughter had her Mom explaining that he seemed to be about her age, responsible and managed to balance it all out with a good sense of humor. Good qualities in a man, Joyce had defended before telling her, "Besides if you misbehave I could always threaten to lock you up with him during a full moon."

"Buffy would save me!" Dawn had declared.

"And protect him from that nasty Cain man. Everytime I read the third book I always worry some hunter will go after Lupin. If he were here I'd know he was safe."

Then the conversation had turned to Oz and how they wished Wolfsbane was real. The subject of Oz turned them to Willow with her Mom suggesting she get Willow to sign in her crush.

Willow had the worst things for the Potions Master. She couldn't explain it, but she couldn't get enough of him. She'd probably read every fanfic written with him in the main role. Tara for some reason thought Willow's crush was just too cute.

Willow had been more then happy to comply with a carefully scrawled Willow Rosenberg loves Severus Snape. Tara had declared that she was jealous, which lead to Willow challenging her to find a crush. Tara asked Dawn if it was all right. As soon as she got the okay she gave Willow a broad smile before carefully, right next to Willow's, writing Tara loves Hermione. Then she drew a little heart between hers and Willow's name. As she began to color in the heart Willow demanded to know why Hermione.

Tara gave them both a secret smile before turning to Willow and saying, "Because she as close to you as I can get."

Willow's face melted in happiness and Dawn laughed at them as they shared a kiss. When Tara pulled away she brushed a strand of hair behind Willow's ear and said softly, "Promise me something?"

"Hmmm..."

"If you ever get the chance to kiss Snape, promise me you will."

Willow had started laughing, "Only if you promise me the same about Hermione."

Laughing together they promised. Dawn had declared them both crazy because it was just a book, right?

"Unfortunately," Tara had said, "Can you imagine how different my life would be if it weren't?"

"I'd still be stuck on the Hellmouth," Willow had pouted, "I didn't start to get into magic till I was sixteen."

"Besides the energies from the Hellmouth would probably give off some kind of block detection or something," Dawn had pointed out.

"Just my luck," Willow had pouted further.

Shortly thereafter Melinda had asked to borrow her Harry Potter book during her free period seeing as she had left her at home. Dawn had agreed and Melinda had come back from her free period Janice in tow.

"Can we sign your book too?" Janice had asked while Melinda had only grinned looking hopeful.

"Ah, okay," Dawn had agreed.

Giggling Melinda had declared her love for Harry. Janice had rolled her eyes and said that Harry was far too much of a goody-goody and then proceeded to carefully transcribe her love for Draco.

Anya and Xander had been next to join in the fun. Anya quickly read all four books with delighted explanations about different characteristics of the books which occasionally lead to stories of her demon days. Somehow they all survived this though Buffy had once declared that she was going to slay the books if Anya didn't stop soon. Once she had read everything Anya had carefully gone over her options before writing down that she was in love with Sirius Black.

"He reminds me of Xander, with his rugged mainlines and all. Plus he's got to be rich to have bought Harry that broom. And he hasn't had an orgasm friend for awhile so he'll be wanting to have a lot of sex," she had explained smiling. Xander had laughed at her before taking the book from her and carefully writing all along the edge of the inner cover Xander loves Anya loves Xander love Anya. Anya had gotten impatient to know who his crush was as he was writing, he wouldn't let her see. She was all worked up by the time he finished and when she saw she melted and began telling him how much she loved him too. Dawn had wisely grabbed her book and made her escape.

Spike had come next, as it turned out he was an avid reader and had already read the whole series. He insisted on being included in the fun and since that had come at the time when Dawn was crushing on him there was no denying letting him sign her book. It had actually been fun. He'd given her a smirk then pretended to be thinking before he very carefully picked a spot to write William the Bloody loves Ginny Weasley. Then he wrote a short note under it, However he will only claim to love her when she comes of age and only if that Malfoy git doesn't realize how great she is. As it turned out Spike was a die hard Draco/Ginny shipper though he didn't have much faith in Draco, until the movie came out. Dawn couldn't count the number of time the two of them had watched the movie together. Everyone had had a wiggins over how much the young Malfoy had reminded them of Spike and Spike for his part was delighted and never complained over watching it. He even asked for it on occasion.

Giles not to be outdone had given her a smile when she explained about everyone signing the book before he chuckled at her and wrote Giles finds Professor McGonagall interesting.

The hardest to convince to sign her name into the book had been Buffy. Xander and Willow had both put in words for Dawn but Buffy had declared that she had no time for reading. Finally Dawn had got her, "Please Buffy, Mom did and I...I just want everyone in it."

Buffy had paused looking gravely at her before saying, "All right, for Mom."

She had then carefully skimmed the forth book before declaring that Bill was hers. Her logic had included that his line of work seemed to go good with hers and he was cool and he had that fang earring.

To Dawn that time was far away. She often wished things could go back to the way they were when they first began to sign her book. Sure by the time Buffy had signed it Joyce had already passed away, but the way things were now she'd even go back to that time because at least then she had Buffy and Xander and Willow and oh just everyone.

This time the big bad was bigger and scarier then even Glory. Spike had went and got himself souled. Xander had left Anya at the alter and Anya had gone back to being a demon and then back to being a human, but her and Xander just couldn't seem to get back together. Dawn missed them as a couple. Without Anya Xander was becoming all jaded and it wigged her out. She missed her happy, jibbing, always going to find the punch line Xander. Buffy was so busy being strong for the potentials she hardly had time for sisterly things. Giles was here and there. Tara was dead. Willow...it hurt Dawn to think of everything that had happened with Willow. It was safe to say Willow was the Wicca who wouldn't. Things had just fallen apart, everything was wrong and worst yet their house was being over run and Dawn was feeling shunted to the side. It...things just couldn't get worse.

"Well here we are," Xander announced as they pulled up to her house.

"Thank Xander," she told him.

"Hey would you be kind enough to grab one of the bag from the back?"

"Sure, what are they?"

"Stakes for the potentials and for Buffy. One can never have enough stakes."

With a slight sigh Dawn grabbed a bag and went in. Xander followed. Remarkably somehow the house was somewhat quiet. They found Willow in the kitchen.

"Hey Dawnie," she greeted, "Would you like an after school snack."

"That would be so good, I have had the worst day."

"Oh? What's so awful in the life of Dawn?"

Dawn smiled, Willow had been trying harder lately to make sure someone kept up with what was happening with her. Dawn supposed it had to do with Willow still feeling guilty over the things that had happened last year. Dawn wasn't going to complain though, it was nice to finally be getting noticed.

Dawn sat herself down on a stool by the island and watched as Willow set down a plate of chocolate chip cookies with the explanation, "I was in the mood for chocolate and Andrew wanted cookies so well I think he actually went overboard. I'll get some milk."

As Willow started getting drinks for the three of them Dawn launched into an explanation, "Well remember how I told you that Melinda and Janice got in a fight? Well today you wouldn't believe what Melind... what's this?"

As she had been talking Dawn had flipped open her book, it had fallen to the back cover. There was weird writing and signs. Indignant and a little worried Dawn looked at Willow suspiciously, "W-Willow did you do something with my book?"

Willow turned around to look at her confused as Xander came up behind her and asked, "What is that?"

"I don't know," Dawn said worriedly as she began to push the book away from her before declaring, "Ow! Ow! Paper cut!"

"Bleeder too," Xander observed.

Dawn hissed in pain and began to pull her hand back, some of her blood flew onto the book. Her eyes widened in fascination as the blood was absorbed by the signs and they started to glow. She grabbed her book and stared at it. She shook it. Then she noticed Xander was going up to Willow, he seemed angry. He was talking to Willow, actually it looked more like he was accusing her of something. That's when Dawn realized she couldn't hear him. As she opened her mouth to scream the world around her began to spin and her book slipped from her fingers and clattered to the floor. 


	3. Promise Kept

Dawn finally managed to let out a shriek as the spinning around her slowed and the world snapped back into focus. The air was slightly chilled, the walls were stone and she was near a desk. She realized she must be in a classroom of sorts.

A girls voice rose behind her in a know-it-all tone, "That isn't possible, one cannot Apparte within the castle."

The girls voice startled Dawn and with another shriek she dropped Xander's bag of carefully whittled stakes. A hand grabbed her and spun her to face him as his voice bellowed, "Who are you? Where did you come from?"

Black eyes, the man had black eyes. They weren't the opaque all encompassing blackness Willow's had gotten when she had gone evil but the fact that they were black elicited a scream from her as she jerked away from him and backpedaled.

"G-G-Get away from me!" she stuttered in full panic mode.

The man seemed startled by the fear in her tone and remained rooted where he stood. That's when she got a good look at him and the class behind him. The man in front of her was intimating to say the least. He had greasy black hair, with those frighteningly black eyes, a large nose and a scowl that looked like it never left his face. He was wearing black robes...wait a moment...robes? So were the students behind him. With slight horror she realized the color of the ties: Gryffindor and Slytherin colors. She had landed herself in Snape's Double Potions class, oh joy.

Her quick assessment of the students made her realize exactly what class she had landed herself in. There was Malfoy in Slytherin colors looking for all the world like someone had slapped him with a Spike stick. There was Hermione with her bushy hair seated next to a pudgy faced boy who looked miserable, had to be Neville. The dark haired boy with the emerald eyes and round glasses had to be Harry. The tall fiery red head seated next to him looking good enough to eat had to be Ron. As her eyes took him in Dawn felt a goofy smile begin to spread her face and she was unable to stop the dreamy sigh that escaped her. Ron looked startled, as if he didn't know how to react to this.

Though the whole exchange had only taken a few seconds it was more then enough to get Snape worked up.

"Blaise Zabini, watch the class! I want a report on who misbehaved as soon as I get back. I will not hesitate to take points from Gryffindor ," he snapped as he grabbed Dawn roughly and began to drag her out of the class.

As they passed Draco Dawn cried, "Wait! I really really have to ask him something."

Snape stopped and gave her a disgruntled angry scowl as Draco started to smirk.

"Is your coloring natural or do you bleach?"

Draco blinked and his smirk faltered.

"Cause it looks natural to me and Spike so totally bleaches his hair. You so do not have his cheekbones though. Oh, and he these metallic blue eyes while yours are just gray. Other then that you could so totally pass for him, if you wanted to dress up like him or something ...for like Halloween or something."

"And who is this Spike?" Draco asked looking both insulted and confused.

"William the Bloody?" Dawn tried.

"William the who?"

"Bloody. He likes to call himself the big bad? He's a bad ass vampire. It's a whole big thing with a chi...Hey!" Dawn was cut off as Snape who had clearly had enough interruptions of his class for one day finished dragging her out of his room. He had no idea what was going on or who this girl was but he was going directly to the Headmaster with this one.

The Headmaster was everything Dawn had envisioned him to be. He was cool, collected and managed to look slightly amused as Snape snapped out his entire story. Snape had drug her into Dumbledore's office and exploded, going on and on and on about how there had been this green swirling light and then this girl show's up. And oh she was also obviously crazy because she had actually sighed at 'Potter's sidekick Weasley' and had then proceed to bombard Draco Malfoy with petty questions and comments. Dawn couldn't believe one person could have so many complaints about the few moments she had actually spent in his presence. What Willow saw in him was beyond Dawn's comprehension. She settled for sitting in a chair, crossing her arms and giving him evil stares as she waited for him to conclude so she could have her turn to talk to the headmaster. This man was so totally getting in trouble when she was though.

Finally he shut up and the Headmaster turned to her looking amused, "That certainly is an interesting tale, perhaps the young lady can shed some light on how she came to be here."

"I-I-I," Dawn stopped and frowned. She herself had only a vague idea on how she had landed herself at Hogworts. Someone had obviously put a spell in her book and her blood had triggered it.

She took a deep breath.

"Well, I'm a key see and somehow I put myself in the lock and gave a little twist. It's hard to even believe I'm here, where I'm from this, all of this is part of a book series and I'm totally here by accident. I mean if I had chosen to come here his class would be the last I'd be landing myself in," Dawn told him slowly, pointing at Snape to emphasis her point. Then she stuck out her tongue at him.

"S-She...Did you see what she just did?" Snape demanded with indigence.

"Act like a child and get treated like one," she shot back.

This caused Snape to growl and start towards her.

"You wouldn't dare hurt me, my sister would have you head," Dawn hissed at him.

This cause Snape to stop and scowl as he asked in disbelief, "You're defending yourself by threatening me with your sister?"

"She's a Slayer and she could so totally kick your ass."

Before Dumbledore could stop them from arguing further and get them to the process of figuring out how to send Dawn home a flash of red light entered the room and disappeared to reveal Willow who was clutching Dawn's Harry Potter book.

"Dawnie?" she asked looking freaked.

"Willow!" Dawn cried as she rushed over to hug her.

"Your here to save me...and...and you used magic?"

"I couldn't leave you here, by the way where is whoa...Dawn how did you do this."

"It so wasn't me. I didn't put that spell in my book..." Dawn told her then froze backing away with a suspiciously look, "I ended up in Snape 's class and and..."

Willow gave her a hurt look.

"...it obviously wasn't you." Dawn concluded.

"Darn tootin." Willow agreed with a nod, "Wait, Snape's class? You actually met..."

Dawn moved back to Willow and turned her to look at the Potions Master , "He's right there. He's the one looking like I totally ruined his day because I disrupted his class and he can't take points from anyone for it."

"Dawn!" Willow scolded.

"What? He started it."

"We should go home right now," Willow told her as she latched her hand onto Dawn's wrist and pulled a bag out of her pocket, "before we make this situation any worse."

"Wait," Dawn told her, "Your promise to Tara."

"My...that...what about Ken..."

"But you promised Tara," Dawn pouted.

Both the Headmaster and Professor Snape had remained quiet throughout the entire conversation because it was well rather odd and neither could think of a good time to jump in and say something. After Dawn's pout the redhead had given a pout before both girl's turned to regard Snape. Snape found himself instinctively taking a step back.

The red head, Willow, handed the book she'd been holding to Dawn and began to move towards him nervously fidgeting as she told him, "Hi... my names Willow Rosen...you probably don't need my last name huh? Um your sorta my um well there are these books...and I probably shouldn't go into that, but I um made a promise that if I ever met you I'd..."

She effectively cut off her own prattling by soundly kissing Snape. After his initial shock Snape found himself kissing her back. The both of them became so lost in each other that they quickly forgot the other occupants of the room until Dawn said, "Um Willow you promised Tara a kiss big emphasis on a kiss and um..."

Startled Willow came to her sense, "Oops. Not suppose to be making with the big smoochies huh?"

Dawn nodded.

Willow gave Snape a big nervous smile as she once again pulled Dawn to her and picked up the bag she had taken out of her pocket, "Okay, we'll just be going now."

As Willow began to raise her hand and throw the bag down Dawn once again called out, "Wait!"

Willow froze and gave Dawn a pleading look.

With an impish grin Dawn looked directly at the Headmaster and said, "Please tell Ginny Weasley that William the Bloody sends his love."

Then she held tightly to Willow and said, "We can go now."

Willow rolled her eyes and threw the bag on the floor. The two girls disappeared in a shower of light leaving behind one smirking Head of Slytherin House and one mildly amused Headmaster. 


	4. Home Again

As soon as Willow and Dawn materialized in the kitchen Xander embraced them both in a tight hug as he sighed, "Oh thank God."

Willow and Dawn were unable to suppress their giggles as they both gave him a quick squeeze back and stepped out of his embrace.

"Did you see his face?" Dawn asked.

"I-I can't believe I did that! You don't think I got him angry do you?"

"Willow," Dawn told her giving her an look, "he loved every second of it."

"You think? Really?"

"Please, his scowl face was so totally less scowly."

A totally confused Xander chose that time to jump into their conversation by saying, "Anyone care to fill in the lost guy."

Dawn gave him a full grin, "You'll never believe where we just were."

"What's all this bloody racket? Can't I get any sleep around here?" Spike asked as he came in yawning.

"Spike, what are you..."

Spike yawned and eyed Willow as her voice tailed off and he explained, "Demon-girl and I got a present for the Bit, wanted to see her get it."

His explanation had Xander frowning, "You and Anya?"

Spike shrugged, "She found it on the Internet asked me to buy it."

By now Dawn attention had refocused, "A present for me? Where?"

Spike shrugged and yawned again at which point Anya wander into the room and gave Spike a hurt look, "Did you ruin it?"

Spike shrugged, "She'll like it anyway, give it to her already. I want to be done with the screaming and jumping."

"Screaming and jumping," Anya asked her eyes widening, "You didn't say anything about..."

"In happiness," Spike explained rolling his eyes, "I'm saying she'll get all excited."

"But only in a good way right?" Anya asked.

"Okay now lets..." Xander interrupted trying to take control of the conversation as Willow cut him off.

"If you two got a present for Dawn why don't you give it to her," Willow tried.

"Okay." Anya shrugged and she left the room.

"Now," Xander started as he turned his attention back to Willow and Dawn, "where did you guys go?"

Willow gave Xander a small smile, "Wait till Anya get back."

"I already am," Anya said as she brought a wrapped package out from behind her back and handed it to Dawn. Dawn let out a squeal of joy and grabbed it ripping the paper.

"Oh Spike, Anya," she exclaimed before she started laughing.

"What?"

"Willow look," Dawn said as she showed the book title to Willow.

"The Sorcerer's Companion: A Guide to the Magical World of Harry Potter," Willow read slowly laughing slightly before she exclaimed, "Oh! Oh! Dawn did you get to see Ron?"

"Yes! He was so so cute," Dawn exclaimed before giving her a slightly confused look, "and older for some reason, but he was still..."

"Um," Anya interrupt, "What are you two going on about?"

"Yea, what'd we miss?" Spike grumbled.

"You'll never believe where we just came from," Willow told them.

Dawn smirked, "And you'll never believe what just happened."

"What? What?" Xander exclaimed, "Enough with the suspense already, what happened?"

"Willow and Snape."

At everyone's confused look Willow and Dawn launched into an excited explanation of their recent adventure. As the group settled around the kitchen's island and over milk and cookie discussed exactly how they thought the adventure had come to pass, and as they asked Dawn and Willow for details on everything Dawn clutched her new book to her chest and smiled. Maybe, just maybe things weren't as bad as she had thought they were. Maybe everything would still turn out all right in the end. 


End file.
